This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. DNA fragment size analysis by flow cytometry has been applied to the analysis of restriction enzyme digest of several bacterial strains of E. coli and S. aureus. Distinct restriction fragment fingerprints were observed and served as the basis for discriminating among the strains of each species.